Multiple light collection and lens combinations with co-located foci for curing optical fibers

Abstract

A device for UV curing a coating or printed ink on a workpiece such as an optical fiber comprises at least two UV light sources equally spaced around a central axis, each UV light source comprising a reflector and a cylindrical lens, and the UV curing device configured to receive a workpiece along the central axis. The reflectors are configured to substantially reduce the emitting angle of light from the UV light sources, thereby directing the light substantially through the cylindrical lenses, the cylindrical lenses focusing the light intensely along a surface of the workpiece.

The invention claimed is: 
     
       1. A device, comprising:
 at least two UV light sources equally spaced around a central axis, each UV light source comprising a housing containing one or more light-emitting semiconductor devices, a compound parabolic reflector attached to the housing, and a cylindrical lens mounted to the compound parabolic reflector, and the device configured to receive a workpiece along the central axis, wherein each compound parabolic reflector includes a plurality of facets. 
 
     
     
       2. The device of  claim 1 , wherein the device is a UV curing device, and wherein the reflectors are configured to substantially reduce an emitting angle of light from the at least two UV light sources, thereby directing UV light substantially through the cylindrical lenses, the cylindrical lenses focusing the light intensely along a surface of the workpiece. 
     
     
       3. The device of  claim 2 , wherein:
 the UV light sources comprise a power source, a controller, a cooling subsystem, and a light emitting subsystem, the light emitting subsystem including coupling electronics, coupling optics and a plurality of semiconductor devices; and 
 the housings contain the UV light sources and include inlets and outlets for cooling subsystem fluid. 
 
     
     
       4. The device of  claim 3 , wherein the plurality of semiconductor devices of the at least two UV light sources comprise UV LED arrays, and wherein UV light is substantially directed and focused along the surface of the workpiece via the reflectors and cylindrical lenses. 
     
     
       5. The device of  claim 3 , wherein the cylindrical lenses are cylindrical Fresnel lenses. 
     
     
       6. The device of  claim 3 , wherein the compound parabolic reflectors comprise hollow reflectors, solid optics using total internal reflection, or dichroic reflectors. 
     
     
       7. The device of  claim 3 , wherein the at least two UV light sources emit UV light with different peak wavelengths. 
     
     
       8. The device of  claim 3 , wherein the cooling subsystem comprises a circulating cooling fluid for dissipating heat from the device and cooling fins mounted on an external surface of the reflectors. 
     
     
       9. A method of UV curing a workpiece, comprising:
 irradiating UV light from at least two UV light sources equally spaced around a central axis of the workpiece; 
 reflecting the irradiated UV light via compound parabolic reflectors, wherein the compound parabolic reflectors substantially reduce an emitting angle of the UV light and wherein a surface of each compound parabolic reflector is at least partially faceted, 
 focusing the reflected UV light via cylindrical lenses substantially on to a surface of the workpiece, and 
 drawing the workpiece substantially along a focus of the cylindrical lenses. 
 
     
     
       10. The method of  claim 9 , wherein drawing the workpiece along the focus comprises drawing at least one of an optical fiber, ribbon, or cable with at least one of a UV-curable coating, polymer, or ink, along the focus. 
     
     
       11. The method of  claim 9 , wherein irradiating the UV light comprises irradiating the UV light from the at least two UV light sources that emit the UV light with different peak wavelengths. 
     
     
       12. The method of  claim 9 , further comprising dissipating heat from an external surface of the reflectors via external fins. 
     
     
       13. The method of  claim 9 , further comprising axially centering a quartz sample tube about the focus of the cylindrical lenses, wherein the quartz sample tube concentrically surrounds the workpiece, and wherein the quartz sample tube is purged with an inert gas. 
     
     
       14. A photoreactive system for UV curing comprising,
 a power supply; 
 a cooling subsystem; and 
 a light emitting subsystem comprising,
 at least two UV LED array light sources, wherein each UV LED array light source is arranged equally spaced about a central axis, a UV curing device configured to receive a workpiece along the central axis; 
 coupling optics for each UV LED array light source, including compound parabolic reflectors and cylindrical lenses, the compound parabolic reflectors configured to substantially direct UV light emitted from the at least two UV LED array light sources to the cylindrical lenses, the cylindrical lenses configured to focus the reflected UV light onto a surface of the workpiece, and 
 a controller, including instructions executable to irradiate UV light from the at least two UV LED array light sources, 
 wherein each compound parabolic reflector comprises a plurality of flat facets and corners connecting the plurality of flat facets to form a parabolic surface of the compound parabolic reflector. 
 
 
     
     
       15. The photoreactive system of  claim 14 , wherein the coupling optics further comprise a quartz sample tube surrounding the workpiece, and axially centered about a focus of the cylindrical lenses, wherein the quartz sample tube is purged with an inert gas. 
     
     
       16. The photoreactive system of  claim 15 , wherein the cooling subsystem comprises cooling fins attached to an external surface of the compound parabolic reflectors. 
     
     
       17. The device of  claim 1 , wherein for each UV light source, a plurality of light-emitting semiconductor devices extends along an axial length of the compound parabolic reflector. 
     
     
       18. The device of  claim 1 , wherein each of the facets is flat, and wherein each compound parabolic reflector includes corners connecting the plurality of the flat facets to form a parabolic surface. 
     
     
       19. The device of  claim 1 , wherein each facet has a curved surface. 
     
     
       20. The device of  claim 1 , wherein for each UV light source, the housing is mechanically fastened to the compound parabolic reflector via a faceplate.